1. Field of the Invention
The present invention relates to a clothes dryer, and particularly, to a structure for a roller capable of supporting a drum inside a clothes dryer.
2. Background of the Invention
Recently, a clothes dryer serves to dry an object to be dried by absorbing moisture inside the object by blowing blast generated by an electric heater or a gas heater into a drum. According to a method for processing humid air generated when drying the object, the clothes dryer is largely classified into an exhaustion-type clothes dryer and a condensation-type clothes dryer.
FIG. 1 is a view showing a clothes dryer in accordance with the conventional art.
Referring to FIG. 1, the conventional clothes dryer comprises a body 10 that forms appearance, a drum 20 rotatably installed in the body 10, a door 30 through which an object to be dried is introduced into the clothes dryer, etc. Although not shown, the conventional clothes dryer further comprises a circulation duct having both ends connected to the drum thus to form a flow path for air circulation; a heater disposed in the circulation duct for heating air; a blowing fan for forcibly circulating air; etc. The condensation-type clothes dryer comprises a heat exchanger for removing moisture included in air exhausted from the drum 20.
The drum 20 is rotated by receiving a driving force, through a belt (not shown), from a motor (not shown) installed at an inner lower side of the body 10. The clothes dryer requires a means configured to prevent the drum 20 to be downwardly deformed due to a load of laundry and a load of the drum 20, and configured to support a lower side of the drum 20 for smooth rotation of the drum 20. For this, a supporting roller 40 is generally installed below the drum 20.
FIGS. 2 and 3 are perspective and sectional views of the supporting roller.
Referring to FIGS. 2 and 3, the supporting roller 40 of the drum 20 includes a roller shaft 41; a roller frame 42 slidably installed at the roller shaft 41 and rotated; a roller outer circumferential portion 43 formed of rubber having an elastic force to support the drum 20, and attached to an outer circumference of the roller frame 42; a bearing 44 disposed between the roller frame 42 and the roller shaft 41, and configured to allow the roller frame 42 to be smoothly rotated; and a triangular pin 45 configured to support the roller frame 42 at both sides so as to prevent the roller frame 42 from being separated from the roller shaft 41.
The supporting roller 40 of the conventional clothes dryer is mounted to the roller shaft 41 by using an oil-less bearing formed between the roller frame 42 and the roller shaft 41. However, when a load supported by the bearing increases, oil included in the oil-less bearing may be discharged out. This may degrade a lubricating characteristic of the supporting roller 40, and may cause noise occurrence and damage of the supporting roller 40. Especially, in the case of 24-inch clothes dryer rather than 27-inch clothes dryer, the above problems may become more severe due to a narrow inner space and an overload.
Furthermore, in the conventional bearing, the roller outer circumferential portion 43 contacting the drum 20 has a convexed portion at a central part thereof. This may cause only parts of the entire region of the roller outer circumferential portion 43 to contact the bearing. As a result, a stress applied to the supporting roller 40 is concentrated on specific regions, thereby shortening the lifespan of the supporting roller 40.